Conventional capsules for pharmaceuticals or other powdered, granular or liquid substances, are two-piece capsules having telescoping bodies. For example, the bodies are generally tubular-shaped having a closed end and an open end. One body is generally larger than the diameter of the other body so that the open end of the larger body can at least partially be slipped over the smaller diameter body. The bodies can be tightly fitted, for example, so that the fill material inside the capsule does not leak out. In some capsules a band may be used to secure the two bodies together.
While such two-piece capsules are known, the design of the conventional two-piece capsule has several limitations and disadvantages. In liquid filled capsules, for example, the cavity within the capsule can include only a single mixture. Hence, different active ingredients that interact with each other, for example, cannot be included within the same capsule. In other words, the capsule is limited to the delivery of only internally compatible ingredients. Further, the contents of the conventional capsule are released at once when the capsule dissolves. Hence, there is no way to alter or modify the release time of the same or different drugs. There are also limited ways to mix incompatible ingredients.
To address these issues, others have developed dosage form capsules that have at least one smaller capsule stored within (inside) a larger capsule. Generally, such capsules require a larger two-piece capsule forming the outer shell of the dosage form and one or more smaller capsules therein storing different mediums. Disadvantages of this arrangement include size limitations of the capsules. For example, the inner capsule has a smaller volume than the outer capsule. Further, the outer capsule can be difficult to swallow if its volume is too large. It can also be difficult to manufacture the capsule-within-a-capsule design. Other attempts to address the limitations of the conventional two-piece capsule include the use of solid particles that are dispersed within a liquid capsule fill. The particles, for example, may be coated with one or more substances to protect them from the liquid component and/or to alter their release rate. Among other limitations, however, such solid/liquid fills are inherently expensive to manufacture. Further, not all drugs are available in solid form and/or amenable to coating.
Therefore, there remains a need for a capsule that overcomes the problems of the conventional capsule. More particularly, there remains a need for a dosage form capsule that provides a dual release of the same or different fill materials at the same and/or different times. There further remains a need for a dosage form capsule that permits the delivery of otherwise incompatible fill materials and active ingredients. There also remains a need for a dual release dosage form capsule that simplifies assembly and filling processes of the capsule.